1. Field of the Invention
The present invention is directed to a resin composition comprising (a) a thermoplastic aromatic polycarbonate resin, (b) a graft co-polymer obtained by copolymerizing ethylene-.alpha.-olefin-diene copolymer and a monomer mixture comprising an aromatic vinyl compound and a vinyl cyanide compound as a main component, (c) a glass filler and (d) carbon fiber. More particularly, the resin composition of the present invention has excellent rigidity, strength, heat resistance, high-impact properties, weathering resistance, appearance and drawdown property, and is swelling resistant.
2. Description of the Related Art
Until now, metal materials, such as aluminum and iron, have been used for fabricating building materials, such as a window panel and a door sash. At present, for a variety of applications, a synthetic resin is also employed. The advantage of a window panel or door sash made of a synthetic resin is primarily a heat insulation function. Other advantages include prevention of moisture condensation and ease of design. Until now, PVC resin has mainly been used as a synthetic resin for these building applications. However, PVC resin is too heavy and also inadequate to heat insulation properties, strength, rigidity and impact resistance, and improvements in these properties are desired.
The performance required of a building material for a window panel and door sash is a specific gravity of 1.40 or less, a flexural modulus of 50,000 kJ/cm.sup.2 or more and a Charpy impact strength of 20 kg/cm.sup.2 or more. Furthermore dimensional accuracy, heat resistance, weathering resistance and also a new material feeling are desired.
An aromatic polycarbonate resin has satisfactory heat resistance and impact resistance, among the above-described properties required of a thermoplastic resin composition for fabricating a window panel and door sash.
Aromatic polycarbonate resin has excellent heat resistance and impact resistance as compared to PVC resin, However, aromatic polycarbonate resin does not exhibit an adequate drawdown property or shaping property at the time of a profile extrusion. This is because the aromatic polycarbonate resin generally has a low melt strength.
Known aromatic polycarbonate resins having a relatively high melt strength include a high viscosity aromatic polycarbonate resin and a branched aromatic polycarbonate resin.
However, these polycarbonate resins used alone are unsuitable for application to profile extrusion having a complex shape in accordance with the present invention, in terms of flowability (throughput rate) and profile extrusion property.
Furthermore, to design a material having a flexural modulus of 50,000 kg/cm.sup.2 or more, an inorganic filler, such as a glass filler, e.g., glass fiber, glass flake, glass bead, etc.; a carbon filler, e.g., carbon black and carbon fiber, etc., and other inorganic fillers are added to the resin in a relatively large amount. However, the addition of these fillers increases the specific gravity, such that the resulting product is too heavy.
The present invention solves the above-described problems of conventional products made of PVC resin, and provides a thermoplastic resin composition suitable for producing a profile extrusion molding product, such as a building material, e.g., a window panel and a door sash, having excellent appearance, rigidity, impact resistance and a new material feeling.